CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-sticky-header-enabled vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>ZPAQ - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-sticky-header-enabled vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy","wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"e3a1d0a4-17b4-42e4-9bc5-d7633b5ec8e4","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"ZPAQ","wgTitle":"ZPAQ","wgCurRevisionId":1220293424,"wgRevisionId":1220293424,"wgArticleId":27604934,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["Wikipedia articles with possible conflicts of interest from October 2013","Articles with topics of unclear notability from October 2013","All articles with topics of unclear notability","Products articles with topics of unclear notability","Articles lacking reliable references from October 2013","All articles lacking reliable references","Articles with multiple maintenance issues","Archive formats","Free data compression software","Open formats","Lossless compression algorithms"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"ZPAQ","wgRelevantArticleId":27604934,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove":[],"wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":20000,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q8063260","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false,"wgGELevelingUpEnabledForUser":false}; RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.cite.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","jquery.makeCollapsible.styles":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready"};RLPAGEMODULES=["ext.cite.ux-enhancements","site","mediawiki.page.ready","jquery.makeCollapsible","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.ReferenceTooltips","ext.gadget.switcher","ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap","ext.popups","ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","ext.cx.uls.quick.actions","wikibase.client.vector-2022","ext.checkUser.clientHints","ext.quicksurveys.init","ext.growthExperiments.SuggestedEditSession"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.cite.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediamessages.styles%7Cjquery.makeCollapsible.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.22"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="ZPAQ - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikipedia.org/wiki/ZPAQ"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=ZPAQ&action=edit"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikipedia.org/wiki/ZPAQ"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikipedia Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="login.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-ZPAQ rootpage-ZPAQ skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" title="Main menu" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Main menu</span> </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z"><span>Main page</span></a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia"><span>Contents</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events"><span>Current events</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x"><span>Random article</span></a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works"><span>About Wikipedia</span></a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia"><span>Contact us</span></a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> Contribute </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia"><span>Help</span></a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia"><span>Learn to edit</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors"><span>Community portal</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes to Wikipedia [r]" accesskey="r"><span>Recent changes</span></a></li><li id="n-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_upload_wizard" title="Add images or other media for use on Wikipedia"><span>Upload file</span></a></li><li id="n-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages"><span>Special pages</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <span class="mw-logo-container skin-invert"> <img class="mw-logo-wordmark" alt="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" style="width: 7.5em; height: 1.125em;"> <img class="mw-logo-tagline" alt="The Free Encyclopedia" src="/static/images/mobile/copyright/wikipedia-tagline-en.svg" width="117" height="13" style="width: 7.3125em; height: 0.8125em;"> </span> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikipedia [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia" aria-label="Search Wikipedia" autocapitalize="sentences" title="Search Wikipedia [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Appearance</span> </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en" class=""><span>Donate</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=ZPAQ" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=ZPAQ" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class=""><span>Log in</span></a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Log in and more options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Personal tools</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="https://donate.wikimedia.org/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en"><span>Donate</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=ZPAQ" title="You are encouraged to create an account and log in; however, it is not mandatory"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Create account</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=ZPAQ" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Log in</span></a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing"><span>learn more</span></a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y"><span>Contributions</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n"><span>Talk</span></a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Archive_format" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Archive_format"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Archive format</span> </div> </a> <button aria-controls="toc-Archive_format-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Archive format subsection</span> </button> <ul id="toc-Archive_format-sublist" class="vector-toc-list"> <li id="toc-ZPAQL_Example" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#ZPAQL_Example"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.1</span> <span>ZPAQL Example</span> </div> </a> <ul id="toc-ZPAQL_Example-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Deduplication" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Deduplication"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.2</span> <span>Deduplication</span> </div> </a> <ul id="toc-Deduplication-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Compression" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Compression"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.3</span> <span>Compression</span> </div> </a> <ul id="toc-Compression-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Error_recovery" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Error_recovery"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.4</span> <span>Error recovery</span> </div> </a> <ul id="toc-Error_recovery-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Basic_usage" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Basic_usage"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Basic usage</span> </div> </a> <button aria-controls="toc-Basic_usage-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Basic usage subsection</span> </button> <ul id="toc-Basic_usage-sublist" class="vector-toc-list"> <li id="toc-Creating_an_archive,_and_updating_an_archive" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Creating_an_archive,_and_updating_an_archive"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Creating an archive, and updating an archive</span> </div> </a> <ul id="toc-Creating_an_archive,_and_updating_an_archive-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Listing_archive_contents" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Listing_archive_contents"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Listing archive contents</span> </div> </a> <ul id="toc-Listing_archive_contents-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Extracting_files" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Extracting_files"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>Extracting files</span> </div> </a> <ul id="toc-Extracting_files-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-History" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#History"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>History</span> </div> </a> <ul id="toc-History-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Related_projects" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Related_projects"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Related projects</span> </div> </a> <ul id="toc-Related_projects-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" title="Table of Contents" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">ZPAQ</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 3 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-3" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">3 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/ZPAQ" title="ZPAQ – German" lang="de" hreflang="de" data-title="ZPAQ" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/ZPAQ" title="ZPAQ – French" lang="fr" hreflang="fr" data-title="ZPAQ" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/ZPAQ" title="ZPAQ – Japanese" lang="ja" hreflang="ja" data-title="ZPAQ" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q8063260#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/ZPAQ" title="View the content page [c]" accesskey="c"><span>Article</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:ZPAQ" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t"><span>Talk</span></a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">English</span> </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/ZPAQ"><span>Read</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=ZPAQ&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=ZPAQ&action=history" title="Past revisions of this page [h]" accesskey="h"><span>View history</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">Tools</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/ZPAQ"><span>Read</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=ZPAQ&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=ZPAQ&action=history"><span>View history</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/ZPAQ" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j"><span>What links here</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/ZPAQ" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k"><span>Related changes</span></a></li><li id="t-upload" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u"><span>Upload file</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=ZPAQ&oldid=1220293424" title="Permanent link to this revision of this page"><span>Permanent link</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=ZPAQ&action=info" title="More information about this page"><span>Page information</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=ZPAQ&id=1220293424&wpFormIdentifier=titleform" title="Information on how to cite this page"><span>Cite this page</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FZPAQ"><span>Get shortened URL</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FZPAQ"><span>Download QR code</span></a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:DownloadAsPdf&page=ZPAQ&action=show-download-screen" title="Download this page as a PDF file"><span>Download as PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=ZPAQ&printable=yes" title="Printable version of this page [p]" accesskey="p"><span>Printable version</span></a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q8063260" title="Structured data on this page hosted by Wikidata [g]" accesskey="g"><span>Wikidata item</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><style data-mw-deduplicate="TemplateStyles:r1248332772">.mw-parser-output .multiple-issues-text{width:95%;margin:0.2em 0}.mw-parser-output .multiple-issues-text>.mw-collapsible-content{margin-top:0.3em}.mw-parser-output .compact-ambox .ambox{border:none;border-collapse:collapse;background-color:transparent;margin:0 0 0 1.6em!important;padding:0!important;width:auto;display:block}body.mediawiki .mw-parser-output .compact-ambox .ambox.mbox-small-left{font-size:100%;width:auto;margin:0}.mw-parser-output .compact-ambox .ambox .mbox-text{padding:0!important;margin:0!important}.mw-parser-output .compact-ambox .ambox .mbox-text-span{display:list-item;line-height:1.5em;list-style-type:disc}body.skin-minerva .mw-parser-output .multiple-issues-text>.mw-collapsible-toggle,.mw-parser-output .compact-ambox .ambox .mbox-image,.mw-parser-output .compact-ambox .ambox .mbox-imageright,.mw-parser-output .compact-ambox .ambox .mbox-empty-cell,.mw-parser-output .compact-ambox .hide-when-compact{display:none}</style><table class="box-Multiple_issues plainlinks metadata ambox ambox-content ambox-multiple_issues compact-ambox" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/b/b4/Ambox_important.svg/40px-Ambox_important.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/b/b4/Ambox_important.svg/60px-Ambox_important.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/b/b4/Ambox_important.svg/80px-Ambox_important.svg.png 2x" data-file-width="40" data-file-height="40" /></span></span></div></td><td class="mbox-text"><div class="mbox-text-span"><div class="multiple-issues-text mw-collapsible"><b>This article has multiple issues.</b> Please help <b><a href="/wiki/Special:EditPage/ZPAQ" title="Special:EditPage/ZPAQ">improve it</a></b> or discuss these issues on the <b><a href="/wiki/Talk:ZPAQ" title="Talk:ZPAQ">talk page</a></b>. <small><i>(<a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove these messages</a>)</i></small> <div class="mw-collapsible-content"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1251242444" /><table class="box-COI plainlinks metadata ambox ambox-content ambox-COI" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span class="skin-invert" typeof="mw:File"><span><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/fe/Unbalanced_scales.svg/45px-Unbalanced_scales.svg.png" decoding="async" width="45" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/fe/Unbalanced_scales.svg/68px-Unbalanced_scales.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/fe/Unbalanced_scales.svg/90px-Unbalanced_scales.svg.png 2x" data-file-width="400" data-file-height="354" /></span></span></div></td><td class="mbox-text"><div class="mbox-text-span"><b> A major contributor to this article appears to have a <a href="/wiki/Wikipedia:Conflict_of_interest" title="Wikipedia:Conflict of interest">close connection</a> with its subject.</b><span class="hide-when-compact"> It may require cleanup to comply with Wikipedia's content policies, particularly <a href="/wiki/Wikipedia:Neutral_point_of_view" title="Wikipedia:Neutral point of view">neutral point of view</a>. Please discuss further on the <a href="/wiki/Talk:ZPAQ" title="Talk:ZPAQ">talk page</a>.</span> <span class="date-container"><i>(<span class="date">October 2013</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1251242444" /><table class="box-Notability plainlinks metadata ambox ambox-content ambox-Notability" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/b/b4/Ambox_important.svg/40px-Ambox_important.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/b/b4/Ambox_important.svg/60px-Ambox_important.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/b/b4/Ambox_important.svg/80px-Ambox_important.svg.png 2x" data-file-width="40" data-file-height="40" /></span></span></div></td><td class="mbox-text"><div class="mbox-text-span">The topic of this article <strong>may not meet Wikipedia's <a href="/wiki/Wikipedia:Notability_(organizations_and_companies)#Products_and_services" title="Wikipedia:Notability (organizations and companies)">notability guidelines for products and services</a></strong>.<span class="hide-when-compact"> Please help to demonstrate the notability of the topic by citing <a href="/wiki/Wikipedia:Reliable_sources" title="Wikipedia:Reliable sources">reliable secondary sources</a> that are <a href="/wiki/Wikipedia:Independent_sources" title="Wikipedia:Independent sources">independent</a> of the topic and provide significant coverage of it beyond a mere trivial mention. If notability cannot be shown, the article is likely to be <a href="/wiki/Wikipedia:Merging" title="Wikipedia:Merging">merged</a>, <a href="/wiki/Wikipedia:Redirect" title="Wikipedia:Redirect">redirected</a>, or <a href="/wiki/Wikipedia:Deletion_policy" title="Wikipedia:Deletion policy">deleted</a>.<br /><small><span class="plainlinks"><i>Find sources:</i> <a rel="nofollow" class="external text" href="https://www.google.com/search?as_eq=wikipedia&q=%22ZPAQ%22">"ZPAQ"</a> – <a rel="nofollow" class="external text" href="https://www.google.com/search?tbm=nws&q=%22ZPAQ%22+-wikipedia&tbs=ar:1">news</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?&q=%22ZPAQ%22&tbs=bkt:s&tbm=bks">newspapers</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?tbs=bks:1&q=%22ZPAQ%22+-wikipedia">books</a> <b>·</b> <a rel="nofollow" class="external text" href="https://scholar.google.com/scholar?q=%22ZPAQ%22">scholar</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.jstor.org/action/doBasicSearch?Query=%22ZPAQ%22&acc=on&wc=on">JSTOR</a></span></small></span> <span class="date-container"><i>(<span class="date">October 2013</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1251242444" /><table class="box-Primary_sources plainlinks metadata ambox ambox-content ambox-Primary_sources" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><a href="/wiki/File:Question_book-new.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/50px-Question_book-new.svg.png" decoding="async" width="50" height="39" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/75px-Question_book-new.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/100px-Question_book-new.svg.png 2x" data-file-width="512" data-file-height="399" /></a></span></div></td><td class="mbox-text"><div class="mbox-text-span">This article <b>relies excessively on <a href="/wiki/Wikipedia:Verifiability" title="Wikipedia:Verifiability">references</a> to <a href="/wiki/Wikipedia:No_original_research#Primary,_secondary_and_tertiary_sources" title="Wikipedia:No original research">primary sources</a></b>.<span class="hide-when-compact"> Please improve this article by adding <a href="/wiki/Wikipedia:No_original_research#Primary,_secondary_and_tertiary_sources" title="Wikipedia:No original research">secondary or tertiary sources</a>. <br /><small><span class="plainlinks"><i>Find sources:</i> <a rel="nofollow" class="external text" href="https://www.google.com/search?as_eq=wikipedia&q=%22ZPAQ%22">"ZPAQ"</a> – <a rel="nofollow" class="external text" href="https://www.google.com/search?tbm=nws&q=%22ZPAQ%22+-wikipedia&tbs=ar:1">news</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?&q=%22ZPAQ%22&tbs=bkt:s&tbm=bks">newspapers</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?tbs=bks:1&q=%22ZPAQ%22+-wikipedia">books</a> <b>·</b> <a rel="nofollow" class="external text" href="https://scholar.google.com/scholar?q=%22ZPAQ%22">scholar</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.jstor.org/action/doBasicSearch?Query=%22ZPAQ%22&acc=on&wc=on">JSTOR</a></span></small></span> <span class="date-container"><i>(<span class="date">October 2013</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> </div> </div><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <style data-mw-deduplicate="TemplateStyles:r1257001546">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data:not(.notheme) div:not(.notheme){background:#1f1f23!important;color:#f8f9fa}}@media(min-width:640px){body.skin--responsive .mw-parser-output .infobox-table{display:table!important}body.skin--responsive .mw-parser-output .infobox-table>caption{display:table-caption!important}body.skin--responsive .mw-parser-output .infobox-table>tbody{display:table-row-group}body.skin--responsive .mw-parser-output .infobox-table tr{display:table-row!important}body.skin--responsive .mw-parser-output .infobox-table th,body.skin--responsive .mw-parser-output .infobox-table td{padding-left:inherit;padding-right:inherit}}</style><table class="infobox vevent"><caption class="infobox-title summary">ZPAQ</caption><tbody><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Programmer" title="Programmer">Developer(s)</a></th><td class="infobox-data"><a href="/wiki/Matt_Mahoney_(computer_scientist)" class="mw-redirect" title="Matt Mahoney (computer scientist)">Matt Mahoney</a></td></tr><tr style="display: none;"><td colspan="2" class="infobox-full-data"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1257001546" /></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Software_release_life_cycle" title="Software release life cycle">Stable release</a></th><td class="infobox-data"><div style="margin:0px;">7.15<sup id="cite_ref-wikidata-dbead55b78bc4dda8057ccaab532fc010a7af22c-v18_1-0" class="reference"><a href="#cite_note-wikidata-dbead55b78bc4dda8057ccaab532fc010a7af22c-v18-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> <span class="mw-valign-text-top" typeof="mw:File/Frameless"><a href="https://www.wikidata.org/wiki/Q8063260?uselang=en#P348" title="Edit this on Wikidata"><img alt="Edit this on Wikidata" src="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20" /></a></span> / 22 September 2016</div></td></tr><tr style="display:none"><td colspan="2"> </td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Repository_(version_control)" title="Repository (version control)">Repository</a></th><td class="infobox-data"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style><div class="plainlist"><ul><li><span class="url"><a rel="nofollow" class="external text" href="https://github.com/zpaq/zpaq">github<wbr />.com<wbr />/zpaq<wbr />/zpaq</a></span> <span class="mw-valign-text-top noprint" typeof="mw:File/Frameless"><a href="https://www.wikidata.org/wiki/Q8063260#P1324" title="Edit this at Wikidata"><img alt="Edit this at Wikidata" src="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20" /></a></span></li></ul> </div></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;">Written in</th><td class="infobox-data"><a href="/wiki/C%2B%2B" title="C++">C++</a></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Operating_system" title="Operating system">Operating system</a></th><td class="infobox-data"><a href="/wiki/Microsoft_Windows" title="Microsoft Windows">Microsoft Windows</a>, <a href="/wiki/Linux" title="Linux">Linux</a></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Computing_platform" title="Computing platform">Platform</a></th><td class="infobox-data"><a href="/wiki/IA-32" title="IA-32">IA-32</a>, <a href="/wiki/X86-64" title="X86-64">x86-64</a></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Software_categories#Categorization_approaches" title="Software categories">Type</a></th><td class="infobox-data"><a href="/wiki/File_archiver" title="File archiver">File archiver</a></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Software_license" title="Software license">License</a></th><td class="infobox-data"><a href="/wiki/MIT_License" title="MIT License">MIT</a>, <a href="/wiki/Public_domain" title="Public domain">Public domain</a></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;">Website</th><td class="infobox-data"><span class="url"><a rel="nofollow" class="external text" href="http://mattmahoney.net/dc/zpaq.html">mattmahoney<wbr />.net<wbr />/dc<wbr />/zpaq<wbr />.html</a></span> <span class="penicon autoconfirmed-show"><span class="mw-valign-text-top" typeof="mw:File/Frameless"><a href="https://www.wikidata.org/wiki/Q8063260?uselang=en#P856" title="Edit this on Wikidata"><img alt="Edit this on Wikidata" src="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20" /></a></span></span></td></tr></tbody></table> <p><b>ZPAQ</b> is an <a href="/wiki/Open-source_software" title="Open-source software">open source</a> <a href="/wiki/Command_line" class="mw-redirect" title="Command line">command line</a> <a href="/wiki/Archiver" class="mw-redirect" title="Archiver">archiver</a> for <a href="/wiki/Microsoft_Windows" title="Microsoft Windows">Windows</a> and <a href="/wiki/Linux" title="Linux">Linux</a>. It uses a journaling or append-only format which can be rolled back to an earlier state to retrieve older versions of files and directories. It supports fast incremental update by adding only files whose last-modified date has changed since the previous update. It compresses using <a href="/wiki/Data_deduplication" title="Data deduplication">deduplication</a> and several algorithms (<a href="/wiki/LZ77" class="mw-redirect" title="LZ77">LZ77</a>, <a href="/wiki/Burrows%E2%80%93Wheeler_transform" title="Burrows–Wheeler transform">BWT</a>, and <a href="/wiki/Context_mixing" title="Context mixing">context mixing</a>) depending on the data type and the selected compression level. To preserve forward and backward compatibility between versions as the compression algorithm is improved, it stores the decompression algorithm in the archive. The ZPAQ source code includes a <a href="/wiki/Public_domain" title="Public domain">public domain</a> <a href="/wiki/API" title="API">API</a>, <b>libzpaq</b>, which provides compression and decompression services to <a href="/wiki/C%2B%2B" title="C++">C++</a> applications. The format is believed to be unencumbered by <a href="/wiki/Patent" title="Patent">patents</a>. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Archive_format">Archive format</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ZPAQ&action=edit&section=1" title="Edit section: Archive format"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Files are saved in the ZPAQ level 2 journaling format.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> The standard defines two formats - streaming and journaling. Only the journaling format supports deduplication, directory attributes, and multiple dated file versions. </p><p>The streaming archive format is designed to be extracted in a single pass. An archive is divided into a sequence of blocks that can be decompressed independently in parallel. Blocks are divided into segments that must be decompressed sequentially in order. Each block header contains a description of the decompression algorithm. Each segment has a header containing an optional file name and an optional comment for meta-data such as size, date, and attributes, and an optional trailing <a href="/wiki/SHA-1" title="SHA-1">SHA-1</a> checksum of the original data for integrity checking. If the file name is omitted, it is assumed to be a continuation of the last named file, which may be in the previous block. Thus, inserting, removing, or reordering the blocks in a streaming archive has the effect of performing the same operations on the data that the blocks represent. </p><p>The journaling format consists of a sequence of transactions, or updates. An update contains 4 types of blocks: a transaction header block, a sequence of data blocks, a corresponding sequence of fragment tables, and a sequence of index blocks. A transaction header block contains the transaction date and a pointer skipping over the data blocks to allow the archive index to be read quickly. The data blocks contain a sequence of file fragments compressed together. The fragment tables give the size and SHA-1 hash of each fragment. The index blocks contain a list of edits to the global archive index. An edit is either a file update or a file deletion. An update includes a file name, last modified date, attributes, and a list of fragment pointers into the current and previous transactions. Fragments may be shared by more than one file. A deletion does not remove any data from the archive, but rather indicates that the file is not to be extracted unless the archive is rolled back to an earlier date. </p><p>The ZPAQ standard does not specify a compression algorithm. Rather, it specifies a format for representing the decompression algorithm in the block headers. Decompression algorithms are written in a language called ZPAQL and stored as a byte code which can either be interpreted or converted directly to 32 or 64 bit x86 code and executed. A ZPAQL program has 3 parts. </p> <ul><li>COMP - An optional chain of context modeling components.</li> <li>HCOMP - Machine code for computing contexts for the COMP components.</li> <li>PCOMP - Optional machine code for post-processing the decoded data.</li></ul> <p>The COMP models are based on <a href="/wiki/PAQ" title="PAQ">PAQ</a>, which compresses one bit at a time using <a href="/wiki/Arithmetic_coding" title="Arithmetic coding">arithmetic coding</a>. There are 9 types of components. Each component takes a context and possibly the predictions of earlier components, and outputs a prediction or probability that the next bit will be a 1. The output of the last component is arithmetic coded. The component types are: </p> <ul><li>CONST - A fixed prediction.</li> <li>CM - Context model. The context is used to look up a prediction in a table. On update, the selected entry is adjusted to reduce the prediction error.</li> <li>ICM - Indirect context model. The context is used to look up an 8 bit state representing a recent bit history. The history selects a prediction as with a CM.</li> <li>MIX - A group of predictions are combined by weighted averaging in the logistic domain, or log(p/(1-p)). The weights are selected by a context. On update, the weights are adjusted to favor the more accurate inputs.</li> <li>MIX2 - A 2 input MIX with weights constrained to add to 1.</li> <li>AVG - A MIX2 with fixed weights.</li> <li>SSE - Secondary symbol estimator. Looks up a prediction from an interpolated table given a context and quantized prediction from another component.</li> <li>ISSE - Indirect secondary symbol estimator. The context selects a bit history as with an ICM, and then the bit history selects a pair of weights to mix the input with a constant 1.</li> <li>MATCH - Searches for the previous occurrence of the context and predicts whatever bit followed, with a strength depending on the length of the match.</li></ul> <p>The HCOMP section computes the contexts for the components in the COMP section. It is a virtual machine whose state is 4 32-bit registers (A, B, C, D), a 16 bit program counter, a condition flag bit, and two memory arrays, one of bytes (M) and one of 32 bit words (H). The beginning of H forms the array of contexts. An <a href="/wiki/Assembly_language" title="Assembly language">assembly language</a>-like program is called once for each coded or decoded byte with that byte as input in A. The final context seen by the COMP section is the computed context combined with the previously seen bits of the current byte. </p><p>The optional PCOMP section is used for post-processing the decoded data. It runs in a separate virtual machine like that of HCOMP. However, unlike the COMP and HCOMP sections which are used for both compression and decompression, the PCOMP section is run only during decompression. The compressor is responsible for performing the inverse operation on the input data prior to coding. </p> <div class="mw-heading mw-heading3"><h3 id="ZPAQL_Example">ZPAQL Example</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ZPAQ&action=edit&section=2" title="Edit section: ZPAQL Example"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>ZPAQL source code uses a textual syntax, with each space-delimited word assembling to one byte in most cases, and comments in parentheses. The following example is the <i>mid</i> configuration, similar to level 5 compression. It describes an ICM-ISSE chain of components taking hashed contexts of orders 0 through 5, a MATCH taking an order 7 context, and as a final step, averaging these bit predictions using a MIX. There is no post-processing. </p> <pre><code style="border:none">comp 3 3 0 0 8 (hh hm ph pm n) 0 icm 5 (order 0...5 chain) 1 isse 13 0 2 isse 17 1 3 isse 18 2 4 isse 18 3 5 isse 19 4 6 match 22 24 (order 7) 7 mix 16 0 7 24 255 (order 1) hcomp c++ *c=a b=c a=0 (save in rotating buffer M) d= 1 hash *d=a (orders 1...5 for isse) b-- d++ hash *d=a b-- d++ hash *d=a b-- d++ hash *d=a b-- d++ hash *d=a b-- d++ hash b-- hash *d=a (order 7 for match) d++ a=*c a<<= 8 *d=a (order 1 for mix) halt end</code> </pre> <p>The COMP parameters describe the log base 2 sizes of the word and byte arrays (hh, hm), 8 bytes each in the HCOMP section and not used in the PCOMP section. There are n = 8 numbered components. The components take parameters describing their table sizes and inputs. In particular, each ISSE takes its input from the previous component, and the MIX takes input from the 7 components starting at 0. The line "5 isse 19 4" says that the ISSE has a table size of 2<sup>19+6</sup> bit histories and takes its input from component 4. </p><p>In the HCOMP section, registers B and C point into the 8 byte rotating array M, and D points to the 8 word array H. M is used to store the last 8 bytes of input from the A register. C points to the head of this buffer. The HASH instruction computes: </p> <pre> a = (a + *b + 512) * 773; </pre> <p>Thus, the code stores context hashes of various orders in H[0]...H[7]. </p> <div class="mw-heading mw-heading3"><h3 id="Deduplication">Deduplication</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ZPAQ&action=edit&section=3" title="Edit section: Deduplication"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>On update, ZPAQ divides the input files into fragments, computes their SHA-1 hashes, and compares them to the hashes stored in the archive. If there is a match, then the fragments are assumed to be identical, and only a pointer to the previously compressed fragment is stored. Otherwise the fragment is packed into a block to be compressed. Block sizes can be up to 16 MiB to 64 MiB depending on the compression level. </p><p>Files are divided into fragments on content-dependent boundaries. Rather than a <a href="/wiki/Rabin_fingerprint" title="Rabin fingerprint">Rabin fingerprint</a>, ZPAQ uses a <a href="/wiki/Rolling_hash" title="Rolling hash">rolling hash</a> that depends on the last 32 bytes that are not predicted by an order 1 context, plus any predicted bytes in between. If the leading 16 bits of the 32 bit hash are all 0, then a fragment boundary is marked. This gives an average fragment size of 64 KiB. </p><p>The rolling hash uses a 256 byte table containing the byte last seen in each possible order-1 context. The hash is updated by adding the next byte and then multiplying either by an odd constant if the byte was predicted or by an even number that is not a multiple of 4 if the byte was not predicted. </p> <div class="mw-heading mw-heading3"><h3 id="Compression">Compression</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ZPAQ&action=edit&section=4" title="Edit section: Compression"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>ZPAQ has 5 compression levels, from fastest to best. At all but the best level, it uses the statistics of the order-1 prediction table used for deduplication to test whether the input appears random. If so, it is stored without compression as a speed optimization. </p><p>ZPAQ will use an E8E9 transform (see: <a href="/wiki/BCJ_(algorithm)" title="BCJ (algorithm)">BCJ</a>) to improve the compression of x86 code typically found in .exe and .dll files. An E8E9 transform scans for CALL and JMP instructions (opcodes E8 and E9 hex) and replaces their relative addresses with absolute addresses. Then it inserts code into the PCOMP section to perform the inverse transform. </p> <div class="mw-heading mw-heading3"><h3 id="Error_recovery">Error recovery</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ZPAQ&action=edit&section=5" title="Edit section: Error recovery"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>ZPAQ lacks error correction but has several features that limit damage if the archive is corrupted. On decompression, all SHA-1 hashes are checked. If the hash does not match or if some other error occurs, then a warning is printed and the block is ignored. Blocks begin with a 13 byte "locator tag" containing a randomly chosen but fixed string to allow start of the next block to be found by scanning. If a data fragment is lost, then all of the files referencing that fragment and the remaining fragments in the block are also lost. If a fragment table is lost, then it can be recovered from a redundant list of fragment sizes stored in the corresponding data block and by recomputing the hashes. In this case, a second hash of the whole data block is checked. If an index block is lost, then the corresponding files are lost. Index blocks are small (16 KiB) in order to limit damage. </p><p>Updates are transacted by appending a temporary transaction header and then updating the header as the last step. If an update is interrupted, then the temporary header signals ZPAQ that no useful data is found after it. The next update will overwrite this excess data. </p> <div class="mw-heading mw-heading2"><h2 id="Basic_usage">Basic usage</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ZPAQ&action=edit&section=6" title="Edit section: Basic usage"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Creating_an_archive,_and_updating_an_archive"><span id="Creating_an_archive.2C_and_updating_an_archive"></span>Creating an archive, and updating an archive</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ZPAQ&action=edit&section=7" title="Edit section: Creating an archive, and updating an archive"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><code>zpaq add directory/archive.zpaq directory/source_directory -mX -key password</code> </p><p>The options <code>-mX</code> (with X being the compression level from 0 to 5) and <code>-key</code> (which performs <a href="/wiki/Advanced_Encryption_Standard" title="Advanced Encryption Standard">AES-256</a> encryption) can be omitted. The 0 compression level does not compress data, but still carries out data deduplication. The compression levels 4 and 5 can be very time-consuming. The default (1) uses simple LZ77 compression. </p> <div class="mw-heading mw-heading3"><h3 id="Listing_archive_contents">Listing archive contents</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ZPAQ&action=edit&section=8" title="Edit section: Listing archive contents"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><code>zpaq list archive.zpaq</code> lists the files and directories of the most recent version. Adding <code>-all</code> will list all versions of all files and directories, in the format <code>version_number/directory/file_name</code>. The output can be further processed with <a href="/wiki/Grep" title="Grep">grep</a> and other tools. </p> <div class="mw-heading mw-heading3"><h3 id="Extracting_files">Extracting files</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ZPAQ&action=edit&section=9" title="Edit section: Extracting files"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><code>zpaq extract archive.zpaq</code> will un-pack the last version of the entire archive in the active directory. <code>zpaq extract backup.zpaq path</code> will only extract the specified directory (or file). Appending the <code>-until N</code> option selects the version, where negative numbers are allowed. -2 would extract the third most recent version of the archive. The optional <code>-to</code> tells ZPAQ where to save the extracted files. </p><p><code>zpaq extract backup.zpaq -all -only "*muppet*"</code> will extract all versions of all files and directories whose name contains "muppet". Different file versions will be placed in different directories (<code>0001/ 0002/ 0003/</code> et cetera). <code>-only</code> is optional. </p> <div class="mw-heading mw-heading2"><h2 id="History">History</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ZPAQ&action=edit&section=10" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li>Feb. 15, 2009 - zpaq 0.01 experimental release.</li> <li>Mar. 12, 2009 - zpaq 1.00 specification finalized guaranteeing backward compatibility.</li> <li>Sept. 29, 2009 - zpaq 1.06, specification updated to v1.01 add locator tags to support self extracting archives.</li> <li>Oct. 14, 2009 - zpaq 1.09 adds ZPAQL to C++ translator as a speed optimization.</li> <li>Sept. 27, 2010 - separate libzpaq 0.01 API.</li> <li>Jan. 21, 2011 - pzpaq 0.01, first multi-threaded version, later incorporated back into zpaq.</li> <li>Nov. 13, 2011 - zpaq 4.00, adds JIT compiler (ZPAQL to x86) eliminating need for external C++ compiler for optimization.</li> <li>Feb. 1, 2012 - zpaq 5.00, specification updated to v2.00 to allow empty COMP section (post-processing only).</li> <li>Sept. 28, 2012 - zpaq 6.00, specification updated to v2.01 adding journaling format.</li> <li>Jan. 23, 2013 - zpaq 6.19, splits development functions to a separate program, zpaqd.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Related_projects">Related projects</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ZPAQ&action=edit&section=11" title="Edit section: Related projects"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="https://quixdb.github.io/squash/">Squash</a>, a compression abstraction layer supporting many <a href="/wiki/Codec" title="Codec">codecs</a>.</li> <li><a rel="nofollow" class="external text" href="http://peazip.sourceforge.net/">PeaZip</a>, an archiver supporting over 150 formats including ZPAQ streaming format extraction.</li> <li><a rel="nofollow" class="external text" href="http://mattmahoney.net/dc/fastqz/">fastqz</a>, a <a href="/wiki/FASTQ_format" title="FASTQ format">FASTQ</a> compressor built using libzpaq.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup></li> <li><a rel="nofollow" class="external text" href="https://github.com/fcorbelli/zpaqfranz">zpaqfranz</a>, Swiss army knife for the serious backup and disaster recovery manager.</li> <li><a rel="nofollow" class="external text" href="https://totalcmd.net/plugring/ZPAQ.html">wcx_zpaq</a>, a packer plug-in (wcx) for Total Commander.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ZPAQ&action=edit&section=12" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-wikidata-dbead55b78bc4dda8057ccaab532fc010a7af22c-v18-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-wikidata-dbead55b78bc4dda8057ccaab532fc010a7af22c-v18_1-0">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://github.com/zpaq/zpaq/releases/tag/7.15">"Release 7.15"</a>. 22 September 2016<span class="reference-accessdate">. Retrieved <span class="nowrap">15 March</span> 2018</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Release+7.15&rft.date=2016-09-22&rft_id=https%3A%2F%2Fgithub.com%2Fzpaq%2Fzpaq%2Freleases%2Ftag%2F7.15&rfr_id=info%3Asid%2Fen.wikipedia.org%3AZPAQ" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFMahoney2013" class="citation web cs1">Mahoney, Matt (3 June 2013). <a rel="nofollow" class="external text" href="https://mattmahoney.net/dc/zpaq202.pdf">"The ZPAQ Open Standard for Highly Compressed Data - Level 2"</a> <span class="cs1-format">(PDF)</span><span class="reference-accessdate">. Retrieved <span class="nowrap">28 May</span> 2023</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+ZPAQ+Open+Standard+for+Highly+Compressed+Data+-+Level+2&rft.date=2013-06-03&rft.aulast=Mahoney&rft.aufirst=Matt&rft_id=https%3A%2F%2Fmattmahoney.net%2Fdc%2Fzpaq202.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AZPAQ" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text">Bonfield JK, Mahoney MV (2013) <a rel="nofollow" class="external text" href="http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0059190">Compression of FASTQ and SAM Format Sequencing Data</a>. PLoS ONE 8(3): e59190. doi:10.1371/journal.pone.0059190</span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.ghisler.ch/board/viewtopic.php?t=42739">"[WCX] ZPAQ"</a>. <i>Total Commander Forums</i><span class="reference-accessdate">. Retrieved <span class="nowrap">10 July</span> 2021</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Total+Commander+Forums&rft.atitle=%5BWCX%5D+ZPAQ&rft_id=https%3A%2F%2Fwww.ghisler.ch%2Fboard%2Fviewtopic.php%3Ft%3D42739&rfr_id=info%3Asid%2Fen.wikipedia.org%3AZPAQ" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ZPAQ&action=edit&section=13" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><span class="official-website"><span class="url"><a rel="nofollow" class="external text" href="http://mattmahoney.net/dc/zpaq.html">Official website</a></span></span> <span class="mw-valign-text-top" typeof="mw:File/Frameless"><a href="https://www.wikidata.org/wiki/Q8063260#P856" title="Edit this at Wikidata"><img alt="Edit this at Wikidata" src="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20" /></a></span></li> <li><a rel="nofollow" class="external text" href="https://github.com/zpaq/zpaq">zpaq</a> on <a href="/wiki/GitHub" title="GitHub">GitHub</a></li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20200222215450/http://www.modejong.com/blog/post15_zpaql_grayscale/index.html">Intro to zpaql with grayscale images</a></li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}</style><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Archive_formats518" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374" /><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Archive_formats" title="Template:Archive formats"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Archive_formats" title="Template talk:Archive formats"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Archive_formats" title="Special:EditPage/Template:Archive formats"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Archive_formats518" style="font-size:114%;margin:0 4em"><a href="/wiki/Archive_format" class="mw-redirect" title="Archive format">Archive formats</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Archiving only</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Ar_(Unix)" title="Ar (Unix)">ar</a></li> <li><a href="/wiki/Cpio" title="Cpio">cpio</a></li> <li><a href="/wiki/Shar_(file_format)" title="Shar (file format)">shar</a></li> <li><a href="/wiki/Tar_(computing)" title="Tar (computing)">tar</a></li> <li><a href="/wiki/LBR_(file_format)" title="LBR (file format)">LBR</a></li> <li><a href="/wiki/Doom_modding" title="Doom modding">WAD</a></li> <li><a href="/wiki/WARC_(file_format)" title="WARC (file format)">WARC</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Compression only</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Brotli" title="Brotli">Brotli</a></li> <li><a href="/wiki/Bzip2" title="Bzip2">bzip2</a></li> <li><a href="/wiki/Compress_(software)" title="Compress (software)">compress</a></li> <li><a href="/wiki/Gzip" title="Gzip">gzip</a></li> <li><a href="/wiki/Zopfli" title="Zopfli">Zopfli</a></li> <li><a href="/wiki/Lempel%E2%80%93Ziv%E2%80%93Markov_chain_algorithm" title="Lempel–Ziv–Markov chain algorithm">LZMA</a></li> <li><a href="/wiki/LZ4_(compression_algorithm)" title="LZ4 (compression algorithm)">LZ4</a></li> <li><a href="/wiki/Lzip" title="Lzip">lzip</a></li> <li><a href="/wiki/Lzop" title="Lzop">lzop</a></li> <li><a href="/wiki/SQ_(program)" title="SQ (program)">SQ</a></li> <li><a href="/wiki/XZ_Utils" title="XZ Utils">xz</a></li> <li><a href="/wiki/Zstd" title="Zstd">Zstandard</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Archiving and compression</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/7z" title="7z">7z</a></li> <li><a href="/wiki/ACE_(compressed_file_format)" title="ACE (compressed file format)">ACE</a></li> <li><a href="/wiki/ARC_(file_format)" title="ARC (file format)">ARC</a></li> <li><a href="/wiki/ARJ" title="ARJ">ARJ</a></li> <li><a href="/wiki/B1_(file_format)" title="B1 (file format)">B1</a></li> <li><a href="/wiki/Cabinet_(file_format)" title="Cabinet (file format)">Cabinet</a></li> <li><a href="/wiki/CFS_(file_format)" title="CFS (file format)">cfs</a></li> <li><a href="/wiki/Compact_Pro" title="Compact Pro">cpt</a></li> <li><a href="/wiki/Dar_(disk_archiver)" title="Dar (disk archiver)">dar</a></li> <li>DGCA</li> <li><a href="/wiki/Apple_Disk_Image" title="Apple Disk Image">.dmg</a></li> <li><a href="/wiki/ALZip" title="ALZip">.egg</a></li> <li><a href="/wiki/KGB_Archiver" title="KGB Archiver">kgb</a></li> <li><a href="/wiki/LHA_(file_format)" title="LHA (file format)">LHA</a></li> <li><a href="/wiki/Lrzip" class="mw-redirect" title="Lrzip">lrzip</a></li> <li><a href="/wiki/LZX" title="LZX">LZX</a></li> <li><a href="/wiki/MPQ_(file_format)" class="mw-redirect" title="MPQ (file format)">MPQ</a></li> <li><a href="/wiki/PeaZip#Native_archive_format" title="PeaZip">PEA</a></li> <li><a href="/wiki/RAR_(file_format)" title="RAR (file format)">RAR</a></li> <li><a href="/wiki/Rzip" title="Rzip">rzip</a></li> <li><a href="/wiki/StuffIt" title="StuffIt">sit</a> <ul><li><a href="/wiki/StuffIt" title="StuffIt">sitx</a></li></ul></li> <li>SQX</li> <li><a href="/wiki/PAQ" title="PAQ">UDA</a></li> <li><a href="/wiki/Xar_(archiver)" title="Xar (archiver)">Xar</a></li> <li><a href="/wiki/Zoo_(file_format)" title="Zoo (file format)">zoo</a></li> <li><a href="/wiki/ZIP_(file_format)" title="ZIP (file format)">ZIP</a></li> <li><a class="mw-selflink selflink">ZPAQ</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Package_format" title="Package format">Software packaging and distribution</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Apk_(file_format)" title="Apk (file format)">apk</a></li> <li><a href="/wiki/App_(file_format)" title="App (file format)">App</a></li> <li><a href="/wiki/APPX" class="mw-redirect" title="APPX">APPX</a></li> <li><a href="/wiki/Deb_(file_format)" title="Deb (file format)">deb</a></li> <li><a href="/wiki/App_(file_format)" title="App (file format)">HAP</a></li> <li><a href="/wiki/.ipa" title=".ipa">ipa</a></li> <li><a href="/wiki/JAR_(file_format)" title="JAR (file format)">JAR</a> <ul><li><a href="/wiki/WAR_(file_format)" title="WAR (file format)">WAR</a></li> <li><a href="/wiki/Java_EE_Connector_Architecture" class="mw-redirect" title="Java EE Connector Architecture">Java RAR</a></li> <li><a href="/wiki/EAR_(file_format)" title="EAR (file format)">EAR</a></li></ul></li> <li><a href="/wiki/Windows_Installer" title="Windows Installer">MSI</a></li> <li><a href="/wiki/App_Installer" title="App Installer">MSIX</a></li> <li><a href="/wiki/Package_(macOS)" title="Package (macOS)">Package (macOS)</a></li> <li><a href="/wiki/RPM_Package_Manager" title="RPM Package Manager">RPM</a></li> <li><a href="/wiki/XAP_(file_format)" title="XAP (file format)">XAP</a></li> <li><a href="/wiki/XAML_Browser_Applications" title="XAML Browser Applications">XBAP</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Document packaging and distribution</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Open_eBook" title="Open eBook">OEB Package Format</a></li> <li><a href="/wiki/EPUB" title="EPUB">OEBPS Container Format</a></li> <li><a href="/wiki/Open_Packaging_Conventions" title="Open Packaging Conventions">Open Packaging Conventions</a></li> <li><a href="/wiki/PAQ" title="PAQ">PAQ</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Symbol_na_class.svg" class="mw-file-description" title="Non-article page"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/6/6a/Symbol_na_class.svg/16px-Symbol_na_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/6/6a/Symbol_na_class.svg/23px-Symbol_na_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/6/6a/Symbol_na_class.svg/31px-Symbol_na_class.svg.png 2x" data-file-width="180" data-file-height="185" /></a></span> <a href="/wiki/Comparison_of_archive_formats" class="mw-redirect" title="Comparison of archive formats">Comparison</a></li> <li><span class="noviewer" typeof="mw:File"><span title="List-Class article"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/16px-Symbol_list_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/23px-Symbol_list_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/31px-Symbol_list_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/List_of_archive_formats" title="List of archive formats">List</a></li> <li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Archive_formats" title="Category:Archive formats">Category</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374" /><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235" /></div><div role="navigation" class="navbox" aria-labelledby="Data_compression_software612" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374" /><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231" /><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Compression_software" title="Template:Compression software"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Compression_software" title="Template talk:Compression software"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Compression_software" title="Special:EditPage/Template:Compression software"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Data_compression_software612" style="font-size:114%;margin:0 4em"><a href="/wiki/Data_compression" title="Data compression">Data compression</a> software</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Comparison_of_file_archivers" title="Comparison of file archivers">Archivers</a> with<br /> compression<br /> <span style="font-size: 85%;">(<a href="/wiki/Comparison_of_file_archivers" title="Comparison of file archivers">comparison</a>)</span></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:7em"><a href="/wiki/Free_software" title="Free software">Free software</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/7-Zip" title="7-Zip">7-Zip</a></li> <li><a href="/wiki/Ark_(software)" title="Ark (software)">Ark</a></li> <li><a href="/wiki/Haiku_Applications#Expander" class="mw-redirect" title="Haiku Applications">Expander</a></li> <li><a href="/wiki/FreeArc" title="FreeArc">FreeArc</a></li> <li><a href="/wiki/GNOME_Archive_Manager" class="mw-redirect" title="GNOME Archive Manager">GNOME Archive Manager</a></li> <li><a href="/wiki/Info-ZIP" title="Info-ZIP">Info-ZIP</a></li> <li><a href="/wiki/KGB_Archiver" title="KGB Archiver">KGB Archiver</a></li> <li><a href="/wiki/PAQ" title="PAQ">PAQ</a></li> <li><a href="/wiki/Pax_(command)" title="Pax (command)">pax</a></li> <li><a href="/wiki/PeaZip" title="PeaZip">PeaZip</a></li> <li><a href="/wiki/XAD_(software)" title="XAD (software)">XAD</a> (decompression only)</li> <li><a href="/wiki/Xarchiver" title="Xarchiver">Xarchiver</a></li> <li><a href="/wiki/Zipeg" title="Zipeg">Zipeg</a></li> <li><a class="mw-selflink selflink">ZPAQ</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7em"><a href="/wiki/Freeware" title="Freeware">Freeware</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Filzip" title="Filzip">Filzip</a></li> <li><a href="/wiki/LHA_(file_format)" title="LHA (file format)">LHA</a></li> <li><a href="/wiki/Lhasa_(computing)" title="Lhasa (computing)">Lhasa</a> (decompression only)</li> <li><a href="/wiki/StuffIt_Expander" title="StuffIt Expander">StuffIt Expander</a> (decompression only)</li> <li><a href="/wiki/The_Unarchiver" title="The Unarchiver">The Unarchiver</a> (decompression only)</li> <li><a href="/wiki/TUGZip" title="TUGZip">TUGZip</a></li> <li><a href="/wiki/ZipGenius" title="ZipGenius">ZipGenius</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7em"><a href="/wiki/Commercial_software" title="Commercial software">Commercial</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ARC_(file_format)" title="ARC (file format)">ARC</a></li> <li><a href="/wiki/ALZip" title="ALZip">ALZip</a></li> <li><a href="/wiki/Archive_Utility" class="mw-redirect" title="Archive Utility">Archive Utility</a></li> <li><a href="/wiki/ARJ" title="ARJ">ARJ</a></li> <li><a href="/wiki/BetterZip" title="BetterZip">BetterZip</a></li> <li><a href="/wiki/MacBinary" title="MacBinary">MacBinary</a></li> <li><a href="/wiki/PKZIP" title="PKZIP">PKZIP/SecureZIP</a></li> <li><a href="/wiki/PowerArchiver" title="PowerArchiver">PowerArchiver</a></li> <li><a href="/wiki/StuffIt" title="StuffIt">StuffIt</a></li> <li><a href="/wiki/WinAce" title="WinAce">WinAce</a></li> <li><a href="/wiki/WinRAR" title="WinRAR">WinRAR</a></li> <li><a href="/wiki/WinZip" title="WinZip">WinZip</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Non-archiving<br />compressors</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:7em">Generic</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Bzip2" title="Bzip2">bzip2</a></li> <li><a href="/wiki/Compress_(software)" title="Compress (software)">compress</a></li> <li><a href="/wiki/Gzip" title="Gzip">gzip</a></li> <li><a href="/wiki/Lzip" title="Lzip">lzip</a></li> <li><a href="/wiki/Lzop" title="Lzop">lzop</a></li> <li><a href="/wiki/Pack_(software)" title="Pack (software)">pack</a></li> <li><a href="/wiki/Rzip" title="Rzip">rzip</a></li> <li><a href="/wiki/Snappy_(compression)" title="Snappy (compression)">Snappy</a></li> <li><a href="/wiki/XZ_Utils" title="XZ Utils">XZ Utils</a></li> <li><a href="/wiki/Zstd" title="Zstd">zstd</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7em"><a href="/wiki/Executable_compression" title="Executable compression">For code</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"><a href="/wiki/UPX" title="UPX">UPX</a></div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Data_compression#Audio" title="Data compression">Audio<br /> compression</a><br /> <span style="font-size: 85%;">(<a href="/wiki/Comparison_of_audio_coding_formats" title="Comparison of audio coding formats">comparison</a>)</span></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:7em;padding-top:5px; padding-bottom:5px"><a href="/wiki/Lossy_compression" title="Lossy compression">Lossy</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Advanced_Audio_Coding" title="Advanced Audio Coding">AAC</a> <ul><li><a href="/wiki/Fraunhofer_FDK_AAC" title="Fraunhofer FDK AAC">Fraunhofer FDK AAC</a></li> <li><a href="/wiki/Nero_AAC_Codec" title="Nero AAC Codec">Nero AAC Codec</a></li> <li><a href="/wiki/FAAC" title="FAAC">FAAC</a></li></ul></li> <li><a href="/wiki/Helix_(multimedia_project)" title="Helix (multimedia project)">Helix DNA Producer</a></li> <li><a href="/wiki/MP3" title="MP3">MP3</a> <ul><li><a href="/wiki/L3enc" title="L3enc">l3enc</a></li> <li><a href="/wiki/LAME" title="LAME">LAME</a></li></ul></li> <li><a href="/wiki/TooLAME" title="TooLAME">TooLAME</a></li> <li><a href="/wiki/Libavcodec" title="Libavcodec">libavcodec</a></li> <li><a href="/wiki/CELT" title="CELT">libcelt</a></li> <li><a href="/wiki/Opus_(audio_format)" title="Opus (audio format)">libopus</a></li> <li><a href="/wiki/Speex" title="Speex">libspeex</a></li> <li><a href="/wiki/Musepack" title="Musepack">Musepack</a></li> <li><a href="/wiki/Vorbis" title="Vorbis">libvorbis</a></li> <li><a href="/wiki/Windows_Media_Encoder" title="Windows Media Encoder">Windows Media Encoder</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7em;padding-top:5px; padding-bottom:5px"><a href="/wiki/Lossless_compression" title="Lossless compression">Lossless</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Apple_Lossless_Audio_Codec" title="Apple Lossless Audio Codec">ALAC</a></li> <li><a href="/wiki/FLAC" title="FLAC">FLAC</a></li> <li><a href="/wiki/Libavcodec" title="Libavcodec">libavcodec</a></li> <li><a href="/wiki/Monkey%27s_Audio" title="Monkey's Audio">Monkey's Audio</a></li> <li><a href="/wiki/Audio_Lossless_Coding" title="Audio Lossless Coding">mp4als</a></li> <li><a href="/wiki/OptimFROG" title="OptimFROG">OptimFROG</a></li> <li><a href="/wiki/Shorten_(codec)" title="Shorten (codec)">Shorten</a></li> <li><a href="/wiki/WavPack" title="WavPack">WavPack</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Data_compression#Video" title="Data compression">Video<br /> compression</a><br /> <span style="font-size: 85%;">(<a href="/wiki/Comparison_of_video_codecs" title="Comparison of video codecs">comparison</a>)</span></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:7em"><a href="/wiki/Lossy_compression" title="Lossy compression">Lossy</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/MPEG-4_Part_2" title="MPEG-4 Part 2">MPEG-4 ASP</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/3ivx" title="3ivx">3ivx</a></li> <li><a href="/wiki/DivX" title="DivX">DivX</a></li> <li><a href="/wiki/Nero_Digital" title="Nero Digital">Nero Digital</a></li> <li><a href="/wiki/FFmpeg" title="FFmpeg">FFmpeg</a></li> <li><a href="/wiki/HDX4" title="HDX4">HDX4</a></li> <li><a href="/wiki/Xvid" title="Xvid">Xvid</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Advanced_Video_Coding" title="Advanced Video Coding">H.264</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/CoreAVC" title="CoreAVC">CoreAVC</a></li> <li>Blu-code</li> <li><a href="/wiki/DivX" title="DivX">DivX</a></li> <li><a href="/wiki/FFmpeg" title="FFmpeg">FFmpeg</a></li> <li><a href="/wiki/Nero_Digital" title="Nero Digital">Nero Digital</a></li> <li><a href="/wiki/OpenH264" title="OpenH264">OpenH264</a></li> <li><a href="/wiki/QuickTime" title="QuickTime">QuickTime</a></li> <li><a href="/wiki/X264" title="X264">x264</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/High_Efficiency_Video_Coding" title="High Efficiency Video Coding">HEVC</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/DivX" title="DivX">DivX</a></li> <li><a href="/wiki/X265" title="X265">x265</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Others</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/CineForm" title="CineForm">CineForm</a></li> <li><a href="/wiki/Cinepak" title="Cinepak">Cinepak</a></li> <li><a href="/wiki/Daala" title="Daala">Daala</a></li> <li><a href="/wiki/Avid_DNxHD" title="Avid DNxHD">DNxHD</a></li> <li><a href="/wiki/Helix_(multimedia_project)" title="Helix (multimedia project)">Helix DNA Producer</a></li> <li><a href="/wiki/Indeo" title="Indeo">Indeo</a></li> <li><a href="/wiki/Libavcodec" title="Libavcodec">libavcodec</a></li> <li><a href="/wiki/Dirac_(video_compression_format)" title="Dirac (video compression format)">Schrödinger (Dirac)</a></li> <li><a href="/wiki/Smart_Bitrate_Control" title="Smart Bitrate Control">SBC</a></li> <li><a href="/wiki/Sorenson_codec" class="mw-redirect" title="Sorenson codec">Sorenson</a></li> <li><a href="/wiki/VP7" class="mw-redirect" title="VP7">VP7</a></li> <li><a href="/wiki/Theora" title="Theora">libtheora</a></li> <li><a href="/wiki/Libvpx" title="Libvpx">libvpx</a></li> <li><a href="/wiki/Windows_Media_Encoder" title="Windows Media Encoder">Windows Media Encoder</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:7em"><a href="/wiki/Lossless_compression" title="Lossless compression">Lossless</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/FFV1" title="FFV1">FFV1</a></li> <li><a href="/wiki/Huffyuv" title="Huffyuv">Huffyuv</a></li> <li><a href="/wiki/Lagarith" title="Lagarith">Lagarith</a></li> <li><a href="/wiki/MSU_Lossless_Video_Codec" title="MSU Lossless Video Codec">MSU Lossless</a></li> <li><a href="/wiki/YULS" title="YULS">YULS</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li>See also: <a href="/wiki/Template:Compression_methods" title="Template:Compression methods">compression methods</a> and <a href="/wiki/Template:Compression_formats" title="Template:Compression formats">compression formats</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374" /><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235" /></div><div role="navigation" class="navbox" aria-labelledby="Free_and_open-source_software510" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374" /><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231" /><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:FOSS" title="Template:FOSS"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:FOSS" title="Template talk:FOSS"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:FOSS" title="Special:EditPage/Template:FOSS"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Free_and_open-source_software510" style="font-size:114%;margin:0 4em"><a href="/wiki/Free_and_open-source_software" title="Free and open-source software">Free and open-source software</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">General</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Alternative_terms_for_free_software" title="Alternative terms for free software">Alternative terms for free software</a></li> <li><a href="/wiki/Comparison_of_open-source_and_closed-source_software" title="Comparison of open-source and closed-source software">Comparison of open-source and closed-source software</a></li> <li><a href="/wiki/Comparison_of_source-code-hosting_facilities" title="Comparison of source-code-hosting facilities">Comparison of source-code-hosting facilities</a></li> <li><a href="/wiki/Free_software" title="Free software">Free software</a></li> <li><a href="/wiki/List_of_free_software_project_directories" title="List of free software project directories">Free software project directories</a></li> <li><a href="/wiki/Gratis_versus_libre" title="Gratis versus libre">Gratis versus libre</a></li> <li><a href="/wiki/Long-term_support" title="Long-term support">Long-term support</a></li> <li><a href="/wiki/Open-source_software" title="Open-source software">Open-source software</a></li> <li><a href="/wiki/Open-source_software_development" title="Open-source software development">Open-source software development</a></li> <li><a href="/wiki/Outline_of_free_software" title="Outline of free software">Outline</a></li> <li><a href="/wiki/Timeline_of_free_and_open-source_software" title="Timeline of free and open-source software">Timeline</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/List_of_free_and_open-source_software_packages" title="List of free and open-source software packages">Software<br />packages</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Comparison_of_free_software_for_audio" title="Comparison of free software for audio">Audio</a></li> <li><a href="/wiki/List_of_open-source_bioinformatics_software" title="List of open-source bioinformatics software">Bioinformatics</a></li> <li><a href="/wiki/List_of_open-source_codecs" title="List of open-source codecs">Codecs</a></li> <li><a href="/wiki/Comparison_of_open-source_configuration_management_software" title="Comparison of open-source configuration management software">Configuration management</a></li> <li><a href="/wiki/Device_driver" title="Device driver">Drivers</a> <ul><li><a href="/wiki/Free_and_open-source_graphics_device_driver" title="Free and open-source graphics device driver">Graphics</a></li> <li><a href="/wiki/Comparison_of_open-source_wireless_drivers" title="Comparison of open-source wireless drivers">Wireless</a></li></ul></li> <li><a href="/wiki/List_of_open-source_health_software" title="List of open-source health software">Health</a></li> <li><a href="/wiki/List_of_open-source_software_for_mathematics" title="List of open-source software for mathematics">Mathematics</a></li> <li><a href="/wiki/List_of_office_suites" title="List of office suites">Office suites</a></li> <li><a href="/wiki/Comparison_of_open-source_operating_systems" title="Comparison of open-source operating systems">Operating systems</a></li> <li><a href="/wiki/List_of_open-source_routing_platforms" title="List of open-source routing platforms">Routing</a></li> <li><a href="/wiki/List_of_free_television_software" title="List of free television software">Television</a></li> <li><a href="/wiki/List_of_open-source_video_games" title="List of open-source video games">Video games</a></li> <li><a href="/wiki/List_of_free_and_open-source_web_applications" title="List of free and open-source web applications">Web applications</a> <ul><li><a href="/wiki/Comparison_of_shopping_cart_software" title="Comparison of shopping cart software">E-commerce</a></li></ul></li> <li><a href="/wiki/List_of_free_and_open-source_Android_applications" title="List of free and open-source Android applications">Android apps</a></li> <li><a href="/wiki/List_of_free_and_open-source_iOS_applications" title="List of free and open-source iOS applications">iOS apps</a></li> <li><a href="/wiki/List_of_commercial_open-source_applications_and_services" title="List of commercial open-source applications and services">Commercial</a></li> <li><a href="/wiki/List_of_formerly_proprietary_software" title="List of formerly proprietary software">Formerly proprietary</a></li> <li><a href="/wiki/List_of_formerly_free_and_open-source_software" class="mw-redirect" title="List of formerly free and open-source software">Formerly open-source</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Community_of_practice" title="Community of practice">Community</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Free_software_movement" title="Free software movement">Free software movement</a></li> <li><a href="/wiki/History_of_free_and_open-source_software" title="History of free and open-source software">History</a></li> <li><a href="/wiki/Open-source-software_movement" class="mw-redirect" title="Open-source-software movement">Open-source-software movement</a></li> <li><a href="/wiki/List_of_free-software_events" title="List of free-software events">Events</a></li> <li><a href="/wiki/Open-source_software_advocacy" title="Open-source software advocacy">Advocacy</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/List_of_free_and_open-source_software_organizations" title="List of free and open-source software organizations">Organisations</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Free_Software_Movement_of_India" title="Free Software Movement of India">Free Software Movement of India</a></li> <li><a href="/wiki/Free_Software_Foundation" title="Free Software Foundation">Free Software Foundation</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Free-software_license" title="Free-software license">Licenses</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Academic_Free_License" title="Academic Free License">AFL</a></li> <li><a href="/wiki/Apache_License" title="Apache License">Apache</a></li> <li><a href="/wiki/Apple_Public_Source_License" title="Apple Public Source License">APSL</a></li> <li><a href="/wiki/Artistic_License" title="Artistic License">Artistic</a></li> <li><a href="/wiki/Beerware" title="Beerware">Beerware</a></li> <li><a href="/wiki/BSD_licenses" title="BSD licenses">BSD</a></li> <li><a href="/wiki/Creative_Commons_license" title="Creative Commons license">Creative Commons</a></li> <li><a href="/wiki/Common_Development_and_Distribution_License" title="Common Development and Distribution License">CDDL</a></li> <li><a href="/wiki/Eclipse_Public_License" title="Eclipse Public License">EPL</a></li> <li><a href="/wiki/Free_Software_Foundation" title="Free Software Foundation">Free Software Foundation</a> <ul><li><a href="/wiki/GNU_General_Public_License" title="GNU General Public License">GNU GPL</a></li> <li><a href="/wiki/GNU_Affero_General_Public_License" title="GNU Affero General Public License">GNU AGPL</a></li> <li><a href="/wiki/GNU_Lesser_General_Public_License" title="GNU Lesser General Public License">GNU LGPL</a></li></ul></li> <li><a href="/wiki/ISC_license" title="ISC license">ISC</a></li> <li><a href="/wiki/MIT_License" title="MIT License">MIT</a></li> <li><a href="/wiki/Mozilla_Public_License" title="Mozilla Public License">MPL</a></li> <li><a href="/wiki/Python_License" title="Python License">Python</a></li> <li><a href="/wiki/Python_Software_Foundation_License" title="Python Software Foundation License">Python Software Foundation License</a></li> <li><a href="/wiki/Shared_Source_Initiative" title="Shared Source Initiative">Shared Source Initiative</a></li> <li><a href="/wiki/Sleepycat_License" class="mw-redirect" title="Sleepycat License">Sleepycat</a></li> <li><a href="/wiki/Unlicense" title="Unlicense">Unlicense</a></li> <li><a href="/wiki/WTFPL" title="WTFPL">WTFPL</a></li> <li><a href="/wiki/Zlib_License" title="Zlib License">zlib</a></li></ul> </div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Types_and_standards23" scope="row" class="navbox-group" style="width:1%">Types and<br /> standards</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Comparison_of_free_and_open-source_software_licenses" title="Comparison of free and open-source software licenses">Comparison of licenses</a></li> <li><a href="/wiki/Contributor_License_Agreement" title="Contributor License Agreement">Contributor License Agreement</a></li> <li><a href="/wiki/Copyleft" title="Copyleft">Copyleft</a></li> <li><a href="/wiki/Debian_Free_Software_Guidelines" class="mw-redirect" title="Debian Free Software Guidelines">Debian Free Software Guidelines</a></li> <li><a href="/wiki/Definition_of_Free_Cultural_Works" title="Definition of Free Cultural Works">Definition of Free Cultural Works</a></li> <li><a href="/wiki/Free_license" title="Free license">Free license</a></li> <li><a href="/wiki/The_Free_Software_Definition" title="The Free Software Definition">The Free Software Definition</a></li> <li><a href="/wiki/The_Open_Source_Definition" title="The Open Source Definition">The Open Source Definition</a></li> <li><a href="/wiki/Open-source_license" title="Open-source license">Open-source license</a></li> <li><a href="/wiki/Permissive_software_license" title="Permissive software license">Permissive software license</a></li> <li><a href="/wiki/Public_domain" title="Public domain">Public domain</a></li></ul> </div></td></tr></tbody></table><div> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Challenges</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Digital_rights_management" title="Digital rights management">Digital rights management</a></li> <li><a href="/wiki/License_proliferation" title="License proliferation">License proliferation</a></li> <li><a href="/wiki/Mozilla_software_rebranded_by_Debian" class="mw-redirect" title="Mozilla software rebranded by Debian">Mozilla software rebranding</a></li> <li><a href="/wiki/Proprietary_device_driver" class="mw-redirect" title="Proprietary device driver">Proprietary device drivers</a></li> <li><a href="/wiki/Proprietary_firmware" title="Proprietary firmware">Proprietary firmware</a></li> <li><a href="/wiki/Proprietary_software" title="Proprietary software">Proprietary software</a></li> <li><a href="/wiki/SCO%E2%80%93Linux_disputes" title="SCO–Linux disputes">SCO/Linux controversies</a></li> <li><a href="/wiki/Software_patents_and_free_software" title="Software patents and free software">Software patents</a></li> <li><a href="/wiki/Open-source_software_security" title="Open-source software security">Software security</a></li> <li><a href="/wiki/Tivoization" title="Tivoization">Tivoization</a></li> <li><a href="/wiki/Trusted_Computing" title="Trusted Computing">Trusted Computing</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related <br />topics</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Fork_(software_development)" title="Fork (software development)">Forking</a></li> <li><i><a href="/wiki/GNU_Manifesto" title="GNU Manifesto">GNU Manifesto</a></i></li> <li><a href="/wiki/Microsoft_Open_Specification_Promise" title="Microsoft Open Specification Promise">Microsoft Open Specification Promise</a></li> <li><a href="/wiki/Open-core_model" title="Open-core model">Open-core model</a></li> <li><a href="/wiki/Open-source_hardware" title="Open-source hardware">Open-source hardware</a></li> <li><a href="/wiki/Shared_Source_Initiative" title="Shared Source Initiative">Shared Source Initiative</a></li> <li><a href="/wiki/Source-available_software" title="Source-available software">Source-available software</a></li> <li><i><a href="/wiki/The_Cathedral_and_the_Bazaar" title="The Cathedral and the Bazaar">The Cathedral and the Bazaar</a></i></li> <li><i><a href="/wiki/Revolution_OS" title="Revolution OS">Revolution OS</a></i></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2" style="font-weight:bold"><div> <ul><li><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Symbol_portal_class.svg" class="mw-file-description" title="Portal"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/e/e2/Symbol_portal_class.svg/20px-Symbol_portal_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/e/e2/Symbol_portal_class.svg/40px-Symbol_portal_class.svg.png 1.5x" data-file-width="180" data-file-height="185" /></a></span> <a href="/wiki/Portal:Free_and_open-source_software" title="Portal:Free and open-source software">Portal</a></li> <li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Free_software" title="Category:Free software">Category</a></li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?useformat=desktop&type=1x1&usesul3=0" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=ZPAQ&oldid=1220293424">https://en.wikipedia.org/w/index.php?title=ZPAQ&oldid=1220293424</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:Archive_formats" title="Category:Archive formats">Archive formats</a></li><li><a href="/wiki/Category:Free_data_compression_software" title="Category:Free data compression software">Free data compression software</a></li><li><a href="/wiki/Category:Open_formats" title="Category:Open formats">Open formats</a></li><li><a href="/wiki/Category:Lossless_compression_algorithms" title="Category:Lossless compression algorithms">Lossless compression algorithms</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:Wikipedia_articles_with_possible_conflicts_of_interest_from_October_2013" title="Category:Wikipedia articles with possible conflicts of interest from October 2013">Wikipedia articles with possible conflicts of interest from October 2013</a></li><li><a href="/wiki/Category:Articles_with_topics_of_unclear_notability_from_October_2013" title="Category:Articles with topics of unclear notability from October 2013">Articles with topics of unclear notability from October 2013</a></li><li><a href="/wiki/Category:All_articles_with_topics_of_unclear_notability" title="Category:All articles with topics of unclear notability">All articles with topics of unclear notability</a></li><li><a href="/wiki/Category:Products_articles_with_topics_of_unclear_notability" title="Category:Products articles with topics of unclear notability">Products articles with topics of unclear notability</a></li><li><a href="/wiki/Category:Articles_lacking_reliable_references_from_October_2013" title="Category:Articles lacking reliable references from October 2013">Articles lacking reliable references from October 2013</a></li><li><a href="/wiki/Category:All_articles_lacking_reliable_references" title="Category:All articles lacking reliable references">All articles lacking reliable references</a></li><li><a href="/wiki/Category:Articles_with_multiple_maintenance_issues" title="Category:Articles with multiple maintenance issues">Articles with multiple maintenance issues</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 22 April 2024, at 22:02<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. By using this site, you agree to the <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use" class="extiw" title="foundation:Special:MyLanguage/Policy:Terms of Use">Terms of Use</a> and <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy" class="extiw" title="foundation:Special:MyLanguage/Policy:Privacy policy">Privacy Policy</a>. Wikipedia® is a registered trademark of the <a rel="nofollow" class="external text" href="https://wikimediafoundation.org/">Wikimedia Foundation, Inc.</a>, a non-profit organization.</li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:About">About Wikipedia</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:General_disclaimer">Disclaimers</a></li> <li id="footer-places-contact"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikipedia.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikipedia.org/w/index.php?title=ZPAQ&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://www.wikimedia.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><picture><source media="(min-width: 500px)" srcset="/static/images/footer/wikimedia-button.svg" width="84" height="29"><img src="/static/images/footer/wikimedia.svg" width="25" height="25" alt="Wikimedia Foundation" lang="en" loading="lazy"></picture></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><picture><source media="(min-width: 500px)" srcset="/w/resources/assets/poweredby_mediawiki.svg" width="88" height="31"><img src="/w/resources/assets/mediawiki_compact.svg" alt="Powered by MediaWiki" lang="en" width="25" height="25" loading="lazy"></picture></a></li> </ul> </footer> </div> </div> </div> <div class="vector-header-container vector-sticky-header-container"> <div id="vector-sticky-header" class="vector-sticky-header"> <div class="vector-sticky-header-start"> <div class="vector-sticky-header-icon-start vector-button-flush-left vector-button-flush-right" aria-hidden="true"> <button class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-sticky-header-search-toggle" tabindex="-1" data-event-name="ui.vector-sticky-search-form.icon"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </button> </div> <div role="search" class="vector-search-box-vue vector-search-box-show-thumbnail vector-search-box"> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail"> <form action="/w/index.php" id="vector-sticky-search-form" class="cdx-search-input cdx-search-input--has-end-button"> <div class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia"> <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <div class="vector-sticky-header-context-bar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-sticky-header-toc" class="vector-dropdown mw-portlet mw-portlet-sticky-header-toc vector-sticky-header-toc vector-button-flush-left" > <input type="checkbox" id="vector-sticky-header-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-sticky-header-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-sticky-header-toc-label" for="vector-sticky-header-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-sticky-header-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div class="vector-sticky-header-context-bar-primary" aria-hidden="true" ><span class="mw-page-title-main">ZPAQ</span></div> </div> </div> <div class="vector-sticky-header-end" aria-hidden="true"> <div class="vector-sticky-header-icons"> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-talk-sticky-header" tabindex="-1" data-event-name="talk-sticky-header"><span class="vector-icon mw-ui-icon-speechBubbles mw-ui-icon-wikimedia-speechBubbles"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-subject-sticky-header" tabindex="-1" data-event-name="subject-sticky-header"><span class="vector-icon mw-ui-icon-article mw-ui-icon-wikimedia-article"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-history-sticky-header" tabindex="-1" data-event-name="history-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-history mw-ui-icon-wikimedia-wikimedia-history"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only mw-watchlink" id="ca-watchstar-sticky-header" tabindex="-1" data-event-name="watch-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-star mw-ui-icon-wikimedia-wikimedia-star"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-edit-sticky-header" tabindex="-1" data-event-name="wikitext-edit-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-wikiText mw-ui-icon-wikimedia-wikimedia-wikiText"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-ve-edit-sticky-header" tabindex="-1" data-event-name="ve-edit-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-edit mw-ui-icon-wikimedia-wikimedia-edit"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-viewsource-sticky-header" tabindex="-1" data-event-name="ve-edit-protected-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-editLock mw-ui-icon-wikimedia-wikimedia-editLock"></span> <span></span> </a> </div> <div class="vector-sticky-header-buttons"> <button class="cdx-button cdx-button--weight-quiet mw-interlanguage-selector" id="p-lang-btn-sticky-header" tabindex="-1" data-event-name="ui.dropdown-p-lang-btn-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-language mw-ui-icon-wikimedia-wikimedia-language"></span> <span>3 languages</span> </button> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive" id="ca-addsection-sticky-header" tabindex="-1" data-event-name="addsection-sticky-header"><span class="vector-icon mw-ui-icon-speechBubbleAdd-progressive mw-ui-icon-wikimedia-speechBubbleAdd-progressive"></span> <span>Add topic</span> </a> </div> <div class="vector-sticky-header-icon-end"> <div class="vector-user-links"> </div> </div> </div> </div> </div> <div class="mw-portlet mw-portlet-dock-bottom emptyPortlet" id="p-dock-bottom"> <ul> </ul> </div> <script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-866f5d587f-hdczx","wgBackendResponseTime":158,"wgPageParseReport":{"limitreport":{"cputime":"0.464","walltime":"0.613","ppvisitednodes":{"value":1891,"limit":1000000},"postexpandincludesize":{"value":143378,"limit":2097152},"templateargumentsize":{"value":16919,"limit":2097152},"expansiondepth":{"value":18,"limit":100},"expensivefunctioncount":{"value":6,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":46467,"limit":5000000},"entityaccesscount":{"value":2,"limit":400},"timingprofile":["100.00% 512.113 1 -total"," 54.78% 280.523 2 Template:Infobox"," 51.79% 265.208 1 Template:Infobox_software"," 33.51% 171.596 7 Template:Wikidata"," 33.22% 170.146 1 Template:Infobox_software/simple"," 21.77% 111.470 1 Template:Multiple_issues"," 20.69% 105.951 9 Template:Navbox"," 15.81% 80.978 1 Template:Archive_formats"," 10.56% 54.080 3 Template:Ambox"," 6.91% 35.387 1 Template:COI"]},"scribunto":{"limitreport-timeusage":{"value":"0.313","limit":"10.000"},"limitreport-memusage":{"value":8072623,"limit":52428800}},"cachereport":{"origin":"mw-web.codfw.main-585dc88b6-vmnpb","timestamp":"20250326231718","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"ZPAQ","url":"https:\/\/en.wikipedia.org\/wiki\/ZPAQ","sameAs":"http:\/\/www.wikidata.org\/entity\/Q8063260","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q8063260","author":{"@type":"Organization","name":"Contributors to Wikimedia projects"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2010-06-05T00:20:31Z","dateModified":"2024-04-22T22:02:20Z","headline":"Incremental Journaling Backup Utility and Archiver"}</script> </body> </html>